Distinct distribution of rare us kshv genotypes in south texas. Implications for kshv epidemiology and evolution

PURPOSE: Kaposi's sarcoma-associated herpesvirus (KSHV, or human herpesvirus 8) is etiologically associated with Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). Although previous studies have assessed the geographic distribution of KSHV genotypes, the molecular epidemiology of KSHV remains largely unknown. The purpose of the present study was to examine the genotypes of KSHV isolates from KS patients in South Texas.METHODS: Eighteen KSHV isolates from 16 KS and 1 PEL patients in South Texas were collected between 1996 and 1998 and analyzed for KSHV subtypes by PCR sequencing of ORFK1 gene and KS330 fragment, and by PCR of ORFK15 gene. DNA sequences were aligned with known sequences and KSHV subtypes were assigned based on sequence variations.RESULTS: Of 18 KSHV isolates, 13 exhibited C subtype, and 5 exhibited A subtype in ORF K1 gene. ORF K15 genotyping showed that 10 of the isolates exhibited M form, of which 9 had C3 subtype. A unique C subtype isolate was found and classified as C6 clade. All of the M form KSHV isolates were found among KS patients over 50 years of age. Conversely, all KS patients under 40 years of age had only the P form KSHV isolates.CONCLUSIONS: In South Texas there is a distinct distribution of C3/M KSHV isolates, which are rarely found in other US regions (1 of 29). The C3/M KSHV genotype is more prevalent in HIV-negative elderly KS patients while the P-form of KSHV is more common among many young AIDS-KS patients.     

Kaposi's sarcoma-associated herpesvirus infection in elderly Jews and non-Jews from New York City

BACKGROUND: Worldwide, Kaposi's sarcoma (KS) occurs in immunocompetent elderly adults, especially men. Elderly Jews have relatively high KS risk, but it is unclear whether this indicates heightened prevalence of KS-associated herpesvirus (KSHV), the KS agent. We studied Jewish and non-Jewish patients at a New York City geriatrics clinic. METHODS: We measured plasma antibodies against K8.1 (a KSHV glycoprotein) by enzyme immunoassay and against viral latency antigens by immunofluorescence assay. Individuals positive by either were considered KSHV-seropositive. Titres were performed for positive subjects. We used polymerase chain reaction to quantify circulating KSHV DNA. RESULTS: Of 467 subjects (median age 80 years), 40 were KSHV-seropositive (8.6%). Seroprevalence was 8.8% among Jews (18 of 204), similar to other religious groups, and did not differ by sex or region of birth. However, K8.1 antibody titres were higher in men than women (geometric mean titre 177 versus 35, P = 0.03) and increased with age (P = 0.02). The K8.1 titres were higher in three people from Central/Eastern Europe (1,280, 1,280, 320), all of whom were Jewish, than in others (geometric mean titre 39, P = 0.006). The single person with detectable circulating KSHV (457 copies/million cells) had the highest titre (5,120). CONCLUSIONS: The KSHV seroprevalence was not elevated among elderly Jews, despite their known high risk for KS. However, among KSHV-seropositive individuals, K8.1 titres were highest in subgroups at greatest risk for KS (men, older individuals, people from Central/Eastern Europe) and may identify individuals with poor immune control of KSHV replication during asymptomatic infection.     

Prevalence of antibodies against Kaposi's sarcoma associated herpes virus (KSHV) complement inhibitory protein (KCP) in KSHV-related diseases and their correlation with clinical parameters

Kaposi's sarcoma-associated herpes virus (KSHV) encodes its own inhibitor of the complement system, designated KSHV complement control protein (KCP). Previously, we detected anti-KCP antibodies in a small group of 22 patients suffering from Kaposi's sarcoma (KS) and KSHV-related lymphoproliferative diseases (Vaccine, 25:8102-9). Anti-KCP antibodies were more prevalent in individuals suffering from KSHV-related lymphomas than KS and also in those with high titer of antibodies against lytic KSHV antigens. Herein we analyze anti-KCP antibodies in 175 individuals originating from three different groups from northern Sweden or Italy, which included patients suffering from classical or HIV-associated KS, Multicentric Castleman's Disease, KSHV-associated solid lymphoma, pleural effusion lymphoma and healthy individuals with detectable KSHV immune response. Our current study confirmed previous observations concerning antibody prevalence but we also analyzed correlations between anti-KCP antibodies and classical KS evolution, clinical stage and viral load in body fluids. Furthermore, we show that patient's anti-KCP antibodies are able to decrease the ability of KCP to inhibit complement. This fact combined with results of statistical analysis suggests that KCP inactivation by specific antibodies may influence progression of classical KS.     

Kaposi's sarcoma: a model of both malignancy and chronic inflammation

Kaposi's sarcoma (KS) is a complex cancer characterized by angioproliferative multifocal tumors of the skin, mucosa and viscera. KS lesions are comprised of both distinctive spindle cells of endothelial origin and a variable inflammatory infiltrate. There are four different epidemiological forms of KS: classic (sporadic), African (endemic), AIDS-associated (epidemic), and immunosupression-associated (iatrogenic). Although these various forms of KS have different environmental and immunological components, the development of each depends upon infection with Kaposi's sarcoma herpesvirus/human herpesvirus-8 (KSHV/HHV8). KSHV encodes an arsenal of gene products that induce cellular proliferation, transformation, cell signaling, cytokine production, immune evasion, antiapoptosis and angiogenesis. Yet, KSHV alone is insufficient to give rise to KS. The exact origin of the tumor cell (spindle cell), which is generally agreed to be a type of endothelial cell, remains elusive. Current evidence supports their derivation from lymphatic endothelium. However, both lymphatic and vascular endothelial cell types can be infected by KSHV in vitro, and recent studies suggest that this virus may reprogram the target cell, thus masking the cell's true origin. It is also possible that the original target cell is an uncommitted progenitor. In addition to the potentially neoplastic spindle cells, the KS lesion also contains dendritic cells, macrophages, plasma cells and lymphocytes. The presence of this admixed immune infiltrate has led to the suggestion that KS may result from reactive hyperproliferation induced by chronic inflammation, and that it is therefore not a true neoplasm. This review details the data that support KS as a model of both oncogenesis and chronic inflammation.     

新疆某市吸毒人群血清KSHV感染调查分析

[目的]初步探讨新疆某市吸毒人群血清KSHV感染特点.[方法]EUSA法检测血清KSHV潜伏期LANA1、溶解期ORF65、K8.1抗原抗体;利用X2检验、Logistic回归分析数据.[结果]共检测223份吸毒者血清,吸毒人群主要以注射吸毒者为主(185/223,83%),KSHV阳性64份,KSHV血清阳性率为28.7%.统计分析显示,年龄、职业、文化程度、婚姻状况以及吸毒年限与KSHV血清阳性率无关;吸毒方式、HIV-1感染与吸毒人群KSHV血清阳性率有相关性,是KSHV感染的危险因素,HIV-1感染对KSHV感染的OR为3.310(95%CI为1.116～9.814).[结论]KSHV普遍存在于该地区吸毒人群中,静脉注射吸毒、HIV-1可能是KSHV血清阳性率的独立危险因素,静脉注射吸毒可能是该人群KSHV传播的主要途径.     

Seroprevalence of Kaposi's sarcoma-associated herpesvirus infection among blood donors from Texas

PURPOSE: Kaposi's sarcoma-associated herpesvirus (KSHV), a gammaherpesvirus recently discovered among AIDS patients with Kaposi's sarcoma, is a potential candidate for screening in blood and plasma donors. While a number of studies have assessed KSHV infection among U.S. blood donors, larger-scale population-based studies would be necessary to develop more refined estimates of the magnitude and variation of KSHV infection across different geographic regions of the U.S. blood supply. The goal of the present study, therefore, was to determine the seroprevalence of KSHV infection and to assess demographic correlates of KSHV infection among south Texas blood donors. METHODS: KSHV infection was determined using specific serologic assays that measure antibodies to KSHV latent and lytic antigens. RESULTS: The overall seroprevalence of KSHV in Texas blood donors (15.0%) is substantially higher than previously reported among blood donor and general population samples in the United States. This high rate of KSHV infection persisted across most of the sociodemographic subgroups under study but was particularly elevated among participants with less than a high school education. The infection rate also increased linearly with age. CONCLUSIONS: The elevated infection rate reported in the present study suggests that screening methods to detect KSHV infection in blood donors should be considered. In view of the etiologic role of KSHV for several malignancies, it would be important for future studies to directly assess the risk of KSHV transmission via blood transfusion.     

Antibodies against Kaposi sarcoma-associated herpes virus (KSHV) complement control protein (KCP) in infected individuals

Kaposi sarcoma-associated herpesvirus (KSHV) is the most important etiopathological factor of Kaposi's sarcoma (KS) and some specific types of malignant lymphomas. One of the viral lytic genes encodes the KSHV complement control protein (KCP), which functionally mimics human complement inhibitors. Although this protein provides an advantage for evading the complement attack, it can serve as target for adaptive immune response. Herein, we identified anti-KCP IgG antibodies in patients with KS and KSHV-related lymphomas. KCP-specific antibodies were only detected in sera of those patients who had high titres of antibodies against lytic or latent KSHV antigens. Complement control protein domain 2 (CCP2) was found to be the most immunogenic part of the KCP protein. Furthermore, pre-incubation of KCP-expressing CHO cells with patient sera containing anti-KCP antibodies resulted in an increased complement deposition when incubated with human serum.     

Kaposi''s sarcoma and HTLV-III: a study in Nigerian adult males.

Sera from 37 adult Nigerian men with Kaposi's sarcoma (KS), 30 contemporaneous controls bearing primary cell carcinoma of the liver (PCL), and 150 healthy non-tumour-bearing negative controls were tested for antibody to human T-cell lymphotropic virus type III/lymphadenopathy associated virus (HTLV-III/LAV) by enzyme-linked immunosorbent assays (ELISA). Certain immunocellular functions were also measured: the chemotactic locomotion of peripheral blood monocytes towards casein, delayed-type cutaneous hypersensitivity reaction to tuberculoprotein and opportunistic infection with the fungus Candida albicans. Sera from all these groups were also tested for markers of previous infections with the viruses cytomegalovirus (CMV), Epstein-Barr virus (EBV), hepatitis B (HBV) and hepatitis A (HAV). All serum samples tested were reproducibly and consistently negative for anti-HTLV-III/LAV. Peripheral blood monocytes from both KS and PCL patients showed profound depression of chemotaxis; similarly all tumour patients gave markedly depressed cutaneous reactivity to tuberculoprotein and uniformly exhibited seropositivity to CMV, EBV, HBV and HAV. A great majority showed evidence of infection with Candida albicans. It is concluded that tropical African KS is not associated with HTLV-III/LAV infection.     

A seroprevalence study of human herpesvirus type 8 (HHV8) in eastern and Central Africa and in the Mediterranean area

Human herpes virus type 8 (HHV8) is the major determinant of Kaposi's sarcoma (KS), a neoplasm with wide geographic variations in incidence rates. To assess the prevalence of HHV8 infection among populations with differing rates of KS, we used sera from 1402 persons (Central Africa: Cameroon, n = 293, age range: 5–40; eastern Africa: Uganda, n = 315, age range: 1–64: Mediterranean area: Egypt, n = 236, age range: 13–19: Italy, blood donors n = 134, age range: 20–67: Italy. HIV seroconverters n = 424, age range: 16–65). Serum samples were tested for antibodies to lytic and latent antigens of HHV8 using two immunofluorescence assays. HHV8 prevalence was evaluated according to geographic area, gender and age groups. Overall, the highest prevalence of HHV8 lytic antigens (47.5%) was recorded among children and adults in Africa. Approximately 40% of children and adolescents from Egypt and of Italian HIV-positive persons (39.9%) were HHV8 seropositive. In eastern and Central Africa and in Egypt, no differences emerged between males and females for both types of HHV8 antibodies. Conversely, Italian females were at lower HHV8 risk than their male counterparts. Moreover the prevalence of HHV8 infection tended to increase with age. This investigation partially confirms that HHV8 infection mirrors incidence rates of KS. The high prevalence of HHV8 infection in newborns, children and adolescents in Egypt, in eastern and in Central Africa strongly suggests the existence of transmission modes other than sexual.     

Serological and virological evidence of non-sexual transmission of human herpesvirus type 8 (HHV8)

To evaluate whether or not human herpesvirus 8 (HHV8) can be transmitted through a non-sexual route a serological survey was carried out in a group of 51 catholic nuns. The seroprevalence rate and the geometrical mean antibody titre to anti-latent HHV8 antigen were similar in nuns and in a group of 60 women, matched by age, in the general population (27 vs. 24%; 1028 vs. 1575, respectively). Moreover, by using nested polymerase chain reaction (PCR), HHV8 DNA sequences were detected in 7 of 16 (43.8%) saliva and peripheral blood mononuclear cells (PBMC) from patients with classical Kaposi's sarcoma (KS) and in 3 out of 7 (42%) AIDS-KS patients. None of 5 HIV positive persons who did not have KS tested positive for HHV8 DNA. HHV8 DNA sequences were also detected in 2 of 12 (17%) saliva and 1 PBMC sample out of 12 healthy HHV8 positive individuals (age range: 30-80 years old). This paper suggests that non-sexual transmission of HHV8 is operating in our geographical setting and saliva may be a potential source of HHV8 spreading in the general population.     

Population survey to determine risk factors for Mycobacterium leprae transmission and infection

BACKGROUND: Not every leprosy patient is equally effective in transmitting Mycobacterium leprae. We studied the spatial distribution of infection (using seropositivity as a marker) in the population to identify which disease characteristics of leprosy patients are important in transmission. METHODS: Clinical data and blood samples for anti-M. leprae ELISA were collected during a cross-sectional survey on five Indonesian islands highly endemic for leprosy. A geographic information system (GIS) was used to define contacts of patients. We investigated spatial clustering of patients and seropositive people and used logistic regression to determine risk factors for seropositivity. RESULTS: Of the 3986 people examined for leprosy, 3271 gave blood. Seroprevalence varied between islands (1.7-8.7%) and correlated significantly with leprosy prevalence. Five clusters of patients and two clusters of seropositives were detected. In multivariate analysis, seropositivity significantly differed by leprosy status, age, sex, and island. Serological status of patients appeared to be the best discriminator of contact groups with higher seroprevalence: contacts of seropositive patients had an adjusted odds ratio (aOR) of 1.75 (95% CI 0.922-3.31). This increased seroprevalence was strongest for contact groups living < or =75 m of two seropositive patients (aOR = 3.07; 95% CI 1.74-5.42). CONCLUSIONS: In this highly endemic area for leprosy, not only household contacts of seropositive patients, but also people living in the vicinity of a seropositive patient were more likely to harbour antibodies against M. leprae. Through measuring the serological status of patients and using a broader definition of contacts, higher risk groups can be more specifically identified.     

Kaposi's sarcoma in a cohort of homosexual and bisexual men. Epidemiology and analysis for cofactors

Acquired immunodeficiency syndrome (AIDS) surveillance data for both the United States and San Francisco indicate that Kaposi's sarcoma is more common in homosexual and bisexual men with AIDS than in other adults with AIDS, and that the proportion of newly diagnosed AIDS cases presenting with Kaposi's sarcoma has been significantly declining over time. The changing epidemiology of Kaposi's sarcoma was analyzed in a well-characterized cohort of homosexual and bisexual men; laboratory and interview data from a sample of these men were evaluated for determinants of and cofactors associated with Kaposi's sarcoma. Among 1,341 men with AIDS, the proportion presenting with Kaposi's sarcoma declined from 79% in 1981 to 25% in 1989. Compared with other men with AIDS, men with Kaposi's sarcoma had a shorter interval from human immunodeficiency virus (HIV) seroconversion to AIDS diagnosis (median, 77 vs. 86 months). Men with and without Kaposi's sarcoma did not significantly differ with respect to number of sexual partners, history of certain sexually transmitted or enteric diseases, use of certain recreational drugs (including nitrite inhalants), or participation in certain specific sexual practices. The decline in Kaposi's sarcoma may at least partly be due to a shorter latency period from infection to disease. Although cofactors for the development of Kaposi's sarcoma may exist, many previously hypothesized agents were not supported by this analysis.     

HIV infection in an Ethiopian prison.

HIV-1 antibody was detected in 6.0 percent of prisoners in an Ethiopian prison. HIV-1 seropositivity was strongly associated with positive VDRL status (RR = 3.7) and recent admission to prison (RR = 3.5). Seropositive prisoners were more likely to have prostitute contacts. No correlation was found between seropositivity and number of sexual contacts, long-term sex partners, or dental extractions. HIV-1 infection in this area may be of recent origin and the high prevalence may reflect rates in the surrounding community.     

Hepatitis C virus infection in family setting

To evaluate risk factors associated with intrafamiliar transmission of hepatitis C virus (HCV), 113 hepatitis C virus index subjects with chronic HCV infection and their 267 family contacts were studied from January 1994 to October 1995. Overall, 16 family contacts (6%) were positive for anti-HCV by ELISA II generation. The prevalence was 11.3% in spouses and 2.9% in other relatives (odds ratios: 4.2; 95% CI: 1.4–12.6). Spouses who had been married to the index cases longer than 20 years had a 7.5–fold risk (95% CI: 1.0–336.3) of HCV seropositivity as compared to those married less than 20 years. In univariate analysis HCV seropositivity was associated with surgical intervention, use of glass syringes and hospitalization. The results of multivariate logistic analysis showed that any parenteral exposure (odds ratios: 3.8; 95% CI: 1.2–12.8) and sexual contact with an anti-HCV index case (odds ratios: 3.0; 95% CI: 1.0–9.4) were both independent predictors of HCV seropositivity among household contacts of HCV positive index cases. These findings indicate that sexual contact and any parenteral exposure both play an independent role in the spread of HCV infection in the family setting.     

Factors associated with survival in Kaposi's sarcoma in patients infected with the human immunodeficiency virus. Clinical Epidemiological Group for AIDS in Aquitaine]

BACKGROUND: To study behavioral risk factors of Kaposi's sarcoma (KS) among HIV infected homosexuals in Bordeaux, southwest France. METHODS: A case-control study was performed within the Aquitaine Cohort. Cases of KS surviving in 1995 and homosexuals were systematically enrolled. For each case, two controls were selected among homosexuals surviving in the cohort. Cases and controls were matched on year of diagnosis of HIV infection. Data collection was based on a self administered questionnaire focusing on use of recreational drugs, detailed sexual practices and sexually transmitted diseases in the year preceeding the diagnosis of HIV infection, in the year after the HIV diagnosis and in the year preceeding the diagnosis of KS (or an equivalent period of time for controls). RESULTS: Twelve cases were matched to 2 controls, 15 cases to one control and 13 cases remained unmatched. Matched analysis identified an association between KS and regular sexual partner (odds ratio = 0.07; 95% confidence interval: 0.01-0.52 and p < 0.001) and active and passive oro-anal intercourse before HIV diagnosis and before KS diagnosis (p = 0.01). In the unmatched analysis including all cases, we found an association between KS and the overall number of sexual partners (p < 0.03) for all periods of interest. CONCLUSIONS: This case-control study identified sexual practices in favor of a sexually transmitted agent of KS.     

深圳市SEN病毒D和H亚型感染的检测与分析

目的　了解深圳市一种新的单链DNA病毒 (SENV)的感染流行状况。方法　以SENV读码框架 1区 (ORF1)核苷酸序列设计引物建立巢式聚合酶链反应 (nPCR)方法。采用多重nPCR对6 0 1份来自不同人群血标本进行SENV DNA(D和H亚型 )检测 ,并对所分离的病毒部分基因进行克隆后测序分析。结果　在乙型肝炎患者、丙型肝炎患者、血液透析患者和吸毒人群SENVDNA阳性率分别为 2 7.8%、2 2 .2 %、2 6 .9%和 39.3% ;在献血人群中 ,体检不合格献血者和丙氨酸转氨酶 (ALT)异常升高献血者SENV阳性率分别为 2 8.1%和 31.3% ,均明显高于体检合格的献血者人群 (15 .1% )的感染率(χ2 =8.2 9,P <0 .0 1和χ2 =6 .0 3,P <0 .0 1)。 6例来自不同人群的SENV D亚型分离株部分核苷酸序列与标准株变异 <6 .8% ;4例来自不同人群SENV H亚型分离株部分核苷酸序列与标准株核苷酸最大变异为 13.5 %。结论　在深圳市高危人群 (献血和吸毒人群及肝炎患者等 )中SENV感染均广泛存在     

Estimating the number of Cubans infected sexually by human immunodeficiency virus using contact tracing data

BACKGROUND: To estimate the yearly number of people in Cuba who are living with human immunodeficiency virus (HIV) and were infected through sexual contact but who have not developed acquired immunodeficiency syndrome (AIDS). Estimation was made directly from the yearly HIV seroprevalence data of the Cuban Partner Notification Programme from 1991 to 2000. METHODS: The generalized removal model for open populations is utilized for the estimation. The total number of known HIV-infected Cubans at each sampling time is used in the prior to provide more reasonable approximations. RESULTS: We estimated a yearly survival rate of 93%. The median estimates for the number of all living asymptomatic HIV-positive Cubans, infected by sexual contact, tripled from 714 in 1991 to 2170 in 2000. The number of unknown HIV-positive Cubans infected sexually is estimated to range from 174 in 1991 to 401 in 2000. CONCLUSIONS: A consistent increase in the number of sexually infected HIV-positive individuals in Cuba from 1991 to 2000 is evident from the estimates. From 1996 onwards more sexually active homosexual/bisexual contacts were traced and consequently more sexually-infected HIV-positives were detected. A consequence of increased detection is the levelling off and subsequent decrease in the number of unknown HIV-positives during this time period. The estimation procedure is useful in estimating prevalent population sizes of epidemiological and public health interest.     

ESAT-6 and CFP-10 can be combined to reduce the cost of testing for Mycobacterium tuberculosis infection, but CFP-10 responses associate with active disease

Commercial tests measuring IFN-gamma responses to ESAT-6 and CFP-10 are available for diagnosing Mycobacterium tuberculosis infection. Measures that minimize cost and complexity will facilitate their application in less-developed countries. We investigated whether overlapping peptides representing both ESAT-6 and CFP-10 are required to detect M. tuberculosis infection in a high TB-burden country, and whether they can be combined in a single pool. ESAT-6 and CFP-10 peptides were compared in IFN-gamma enzyme-linked immunospot (ELISPOT) in 183 HIV-negative smear-positive TB cases and 1673 HIV-negative household contacts. Separate peptide pools for each antigen were compared with a combined pool in 498 contacts. Forty per cent of responsive contacts recognized both antigens, 51% only ESAT-6 and 10% only CFP-10, whereas 56% of responsive cases recognized both antigens, 30% only ESAT-6 and 13% only CFP-10. Accordingly, CFP-10 response rates were higher for TB cases (odds ratio 2.409, P<0.001). Low purified protein derivative response rates indicated that responses to CFP-10 only were non-specific in contacts. Agreement between peptides in separate versus combined pools was good (kappa=0.758, r=0.840). Therefore a combined ESAT-6/CFP-10 peptide pool provided maximum sensitivity and efficiency, but CFP-10 was mainly required to detect active disease.     

Kaposi's sarcoma in Tunisia. Review of 91 cases]

The sickness of Kaposi's sarcoma (KS) knows, currently, a renewal of interest since the emergence of 2 new forms: the iatrogenic KS and the epidemic KS. Through a retrospective study on 21 years (1978 to 1998) we have tried to specify the epidemiologic and clinical characters of KS in Tunisia. Our study interests 91 patients: 85 cases of classic KS (94%), 4 cases of iatrogenic KS and 2 cases of epidemic KS. The incidence of iatrogenic KS in renal transplant recipients in our study is 1.9%. A male predominance is found in the 3 forms. The mean age of beginning was 60 years in classic KS and more lower in the 2 other forms (31 years in iatrogenic KS and 46 years in epidemic KS). A predominance of lesions in the lower limbs was found in the 3 forms. The visceral locations was more frequent in iatrogenic KS (3 cases) while it has been found in only 1 case of classic KS. In Tunisia, the classic KS is the most frequent form. In iatrogenic and epidemic KS, visceral lésions are frequent and must be researched systematically.     

Prevalence and risk factors of hepatitis C in HIV-negative homosexual men in Sydney, Australia

OBJECTIVE: To determine the prevalence and risk factors for hepatitis C (HCV) in HIV-negative homosexual men in Sydney. METHODS: A cohort study was conducted in a sample of community-based, HIV-negative, homosexual men in Sydney. Participants underwent a face-to-face interview regarding sexual behaviour, sexually transmissible infections, and injecting drug use (IDU). RESULTS: Eight hundred and twenty-four men consented to HCV testing, and the prevalence was 0.85% (95% CI 0.34-1.74). HCV seropositivity was strongly associated with a history of IDU (OR = 60.43, 95% CI 6.70-544.79). All HCV seropositive individuals reported a history of either IDU or other means by which they may have had parenteral exposure to HCV. There was no evidence of an independent association between sexual behaviour and HCV infection. CONCLUSION: The prevalence of HCV in this cohort was about the same as in the general population in Australia, and there was no evidence for sexual transmission in this population.